N N. N N C C N N C C O O N N C C O O T T N N C C O O T T C C.
I N T R O T O C O M P U T E R N E T W O R K S ( N E W)
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Transcript of I N T R O T O C O M P U T E R N E T W O R K S ( N E W)
INTRODUCTION TO COMPUTER NETWORKS
DOSEN: M. YAHYA
Networks
What is a network?
Collection of computers and devices connected via communications devices and transmissionmedia
NetworksWhat is a local area network (LAN)?
Network in limited geographical area such as home or office building Metropolitan area
network (MAN) connects LANs in city or town
NetworksWhat is a wide area network (WAN)?
Network that covers large geographic area using many types of media
Internet is world’s largest WAN
NetworksWhat is a client/server network? One or more computers
act as server and other computers, or clients, access server
Networks
What is a peer-to-peer network?
Simple network that connects fewer than 10 computers
Each computer, or peer, has equal capabilities
Networks
What is Internet peer-to-peer (P2P)? Enables users to
connect to each other’s hard disks and exchange files directly
Networks What is a bus network?
All computers and devices connect to central cable,or bus
Example of network topology (layout of devices in network) Popular topologies are
bus, ring, and star
NetworksWhat is a ring network?
Cable forms closed ring, or loop, with all computers and devices arranged along ring
Data travels from device to device around entire ring, in one direction
NetworksWhat is a star network?
All devices connect to a central device, called hub
All data transferred from one computer to another passes through hub
Networks What are Ethernet and token ring?
Ethernet technology allows computers to contend for access to network
If two computers send data at same time, a collision occurs and computers must send again
Token ring technology controls access to network by requiring devices to pass a special signal, called token
Networks What are TCP/IP and 802.11? TCP/IP (Transmission Control Protocol/Internet
Protocol) technology transmits data by breaking it up into small pieces, or packets Commonly used for Internet transmissions
802.11 is family of standards for wireless LANs
Networks What is Bluetooth?
Short-range radio waves transmitdatabetweenBluetoothdevices
NetworksWhat are IrDA, RFID, and Wireless Applications Protocol (WAP)?
IrDAIrDAspecification allows data to be transferred wirelessly via infrared light waves
IrDAIrDAspecification allows data to be transferred wirelessly via infrared light waves
Wireless Applications Wireless Applications Protocol (WAP)Protocol (WAP) allow wireless mobile devices to access Internet
Wireless Applications Wireless Applications Protocol (WAP)Protocol (WAP) allow wireless mobile devices to access Internet
Radio Frequency Radio Frequency Identification (RFID)Identification (RFID) uses radio signals to communicatewith a tag placed in an object
Radio Frequency Radio Frequency Identification (RFID)Identification (RFID) uses radio signals to communicatewith a tag placed in an object
Networks What is an intranet?
Extranet allows customers or suppliers to access part of company’s intranet
Typically includes connection to Internet
Makes information accessible to employees
Internal network that uses Internet technologies
Communications What are computer communications?
set-top boxes
mainframecomputers
smartphones
notebookcomputers servers
Web-enabledPDAs
desktopcomputers
Tablet PCs
GPS receivers
Process in which two or more computers or devices transfer data, instructions, and information
Sending device — initiates
instruction to transmit data, instructions, or
information
What is needed for successful communications?
Communications
Communications device — connects the communications
channel to the receiving device
Receiving device — accepts
transmission of data, instructions, or
information
Communications device — connects
the sending device to the communications
channel
Communications channel — media
on which data, instructions, or
information travel
Uses of Computer Communications What are some uses of communications technology?
WebWebWebWebInternetInternetInternetInternet E-MailE-MailE-MailE-Mail
InstantInstantMessagingMessaging
InstantInstantMessagingMessaging FTPFTPFTPFTPNewsgroupsNewsgroupsNewsgroupsNewsgroupsChat RoomsChat RoomsChat RoomsChat Rooms
WebWebFoldersFolders
WebWebFoldersFolders
Fax Machine Fax Machine or Computer or Computer Fax/ModemFax/Modem
Fax Machine Fax Machine or Computer or Computer Fax/ModemFax/Modem
VideoVideoConferencingConferencing
VideoVideoConferencingConferencing
Uses of Computer Communications What are Internet telephony and Internet
printing?
Internet printing Internet printing allows you to print to network printer from anywhere in
the world
Internet telephonyInternet telephony enables you to talk
to other people over the InternetSometimes called
Voice over IPVoice over IP
Uses of Computer Communications What are Web services?
Software that enables programmers to create applications that communicate with other remote computers
Uses of Computer CommunicationsWhat are collaboration and groupware?
Microsoft’s NetMeeting allows collaboration
Groupware is softwarethat allows peopleto shareinformation
Collaboration is working with other users connected to a server
Uses of Computer CommunicationsWhat are public Internet access points and cybercafés? Public Internet access
point allows wireless connection to Internet in public location
Cybercafé is coffee house that provides computers with Internet access
Uses of Computer Communications What is a global positioning system (GPS)?
Step 1.GPS satellites orbit Earth. Every thousandth of a second, each satellite sends a signal that indicates its current position to the GPS server.
Step 2.A GPS receiver (such as in a car, a PDA, a watch, a handheld device, or a collar) determines its location on Earth by analyzing at least 3 separate satellite signals from the 24 satellites in orbit.
Uses of Computer Communications What are voice mail and wireless messaging services?
Voice mail is voice message converted to digital form Wireless messaging services include:
Text Messaging Instant Messaging Picture Messaging
Communications Software What is communications software?
Programs that help users establish connection to Internet, other network, or another computer Programs that help users
manage transmission of data, instructions, and information
Programs that provide an interface for users to communicate with one another
Communications Software What is an example of communications software?
Step 1. After you start the New Connection Wizard and select Connect to the Internet and Set up my connection manually in the dialog boxes, click Connect using a dial-up modem.
Step 2. Enter the name of your Internet service provider.
Step 3. Enter your Internet service provider’stelephone number.
Step 4. Enter your account information.
Step 5. Click the Finish button to create the Internet connection.
Configures home or office network and connects devices to existing network
Communications Over the Telephone NetworkWhat is the public switched telephone network (PSTN)?
Worldwide telephone system that handles voice-oriented telephone calls
Communications Over the Telephone Network What is a dial-up line?
Temporary connection using telephone line for communications
Costs no more than making regular call
Computers at any two locations can establish a connection using modems and telephone network
Communications Over the Telephone Network What is a dedicated line?
Four types are ISDN line, DSL, T-carrier line, and ATM
Always-on connection between two communications devices
Communications Over the Telephone Network What is an ADSL (asymmetric digital subscriber line)?
Popular type of DSL (Digital Subscriber Line)
Faster when receiving data than when sending data Ideal for
Internet access
Communications Devices What are examples of communications devices?
Common types are dial-up modems, ISDN and DSL modems, cable modems, network cards,
wireless access points, routers, and hubs
ISDN and DSL modems send and receive data from ISDN
and DSL lines
Communications Devices What is a dial-up modem? Converts digital signals to analog signals and vice versa Notebook computers often use PC Card modem
Communications Devices What are ISDN and DSL modems?
Communications devices that send and receive digital ISDN and DSL signals
Communications devices that send and receive digital ISDN and DSL signals
Usually external devices in which one end connects to a telephone line and the other
end connects to a port on the system unit
Usually external devices in which one end connects to a telephone line and the other
end connects to a port on the system unit
Communications Devices What is a cable modem?
Sends and receives data over cable television network
Much faster than dial-up modem or ISDN
Sometimes called a broadband modem
Communications Devices What is a network card?
Adapter card, PC Card, or compact flash card that enables computer or device to access network
Sometimes called network interface card (NIC)
Communications Devices What is a wireless access point?
Central communications device that allows computers and devices to transfer data wirelessly among themselves or to wired network
Communications Devices What is a router?
Connects computers and transmits data to correct destination on network
Routers forward data on Internet using fastest available path
Communications Devices
What is a hub?
Device that provides central point for cables in network
Home NetworksWhat is a home network?
Multiple computers connected in home
Several types of home networks Ethernet — connect
computers via cable Powerline cable —
use electrical lines in house Phoneline — use telephone lines HomeRF (radio frequency) — wireless
Communications Channel What is a channel? Transmission media on which data travels in communications system
Bandwidth is amount of data that can travel over channel
Transmission media are materials capable of carrying one or more signals
Communications ChannelHow is a request sent over the Internet using a communications channel?
Step 1. The sending device requests information using either a physical transmission media or a wireless transmission media.
Step 2. When the request leaves the ISP, it travels over T1 lines, microwave stations, earth-based stations, and communications satellites until it reaches the Internet backbone.
Step 3. The request travels over T3 lines along the Internet backbone.
Step 4. The Request travels over T1 lines until it reaches the destination network server.
Communications ChannelHow is a request sent over the Internet using a communications channel?
The Dawn of The Internet (Video)
Physical Transmission MediaWhat is physical transmission media?
Transfer Rates for Various Types of LANs Using Physical Transmission Media
Wire, cable, and other tangible materials used to send communications signals
Physical Transmission Media What are twisted-pair cable and coaxial cable?
Twisted-pair cable is used for telephone systems and network cabling
Physical Transmission Media What is fiber-optic cable?
Capable of carrying significantly more data at faster speeds than wire cables
Less susceptible to interference (noise) and, therefore, more secure
Smaller size (thinner and lighter)
Wireless Transmission Media What is wireless transmission media?
Used when inconvenient, impractical, or impossible to install cables
Includes Bluetooth and IrDA
Wireless Transmission Media What are broadcast radio and cellular radio?
Broadcast radio distributes radio signals over long and short distances
Cellular radio is form of broadcast radio used for mobile communications
Wireless Transmission Media What is a microwave station?
Earth-based reflective dish used for microwave communications
Must transmit in straight line with no obstructions
Wireless Transmission Media What is a communications satellite? Space station
that receives microwave signals from earth-based station, amplifies signals, and broadcasts signals back to any number of earth-based stations